1. Field of Invention
The invention relates to a semiconductor structure and, in particular, to a semiconductor structure of a liquid crystal display (LCD).
2. Related Art
In recent years, there has been a lot of progress in optoelectronic techniques. The coming digital era also pushes the rapid development in the LCD market. The LCD's have the advantages of high quality, small volume, light weight, low driving voltage, and low power consumption. Therefore, they are widely used in personal digital assistants (PDA), mobile phones, video cameras, laptop computers, desktop displays, vehicle displays, and projective televisions. They have gradually replaced the traditional cathode ray tubes (CRT) and become the main stream of displays.
The LCD is a display device that uses the properties of liquid crystals to achieve the display effects. Since it is more flexible in the aspects of size and weight than the conventional CRT, it is often used in various personal systems. Such systems can be as small as mobile phones, PDA's, and digital cameras and as large as television and commercial advertisement boards.
The reason why the LCD is more flexible in the aspects of size and weight than the CRT is that most parts and devices of the LCD are flat. Therefore, LCDs can be cut into appropriate sizes according to the applications. They are also more compact than the CRTs.
In the LCD fabrication processes, photo masks with different patterns are used to define films of different patterns. However, it is well-known that photo masks are expensive. More photo masks cost more. Beside, the production time takes more. Therefore, it would benefit the fabrication cost reduction and the product competitive promotion if the number of required photo masks can be decreased.